CQL 3.02; Find all positions with a mate with doubble check and the black king in the middle of the board. ; A mirror mate is a Mating position in which all (eight) neighboring fields of the mated king are unoccupied.
(match
:pgn heijden.pgn
:output DoubleCheckMateMiddleOfBoard.pgn
(position
:mate
:attackcount A k 2
k[b-g2-7]
)
)

After executing this with "> cql DoubleCheckMateMiddleOfBoard.cql" there are 37 studies found in the Harold van der Heijden Database 2015.NB. When you see {MATCH} in the text, it means that cql has found the position asked for.

Below only 1 study is presented:

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"Even the laziest King flees wildly in the face of a double check! - Aaron Nimzowitsch."